mirror of https://github.com/hak5/bolt.git
131 lines
3.2 KiB
Go
131 lines
3.2 KiB
Go
package bolt
|
|
|
|
import (
|
|
"fmt"
|
|
"os"
|
|
"unsafe"
|
|
)
|
|
|
|
const pageHeaderSize = int(unsafe.Offsetof(((*page)(nil)).ptr))
|
|
|
|
const maxAllocSize = 0xFFFFFFF
|
|
const minKeysPerPage = 2
|
|
const maxNodesPerPage = 65535
|
|
|
|
const branchPageElementSize = int(unsafe.Sizeof(branchPageElement{}))
|
|
const leafPageElementSize = int(unsafe.Sizeof(leafPageElement{}))
|
|
|
|
const (
|
|
branchPageFlag = 0x01
|
|
leafPageFlag = 0x02
|
|
metaPageFlag = 0x04
|
|
freelistPageFlag = 0x10
|
|
)
|
|
|
|
const (
|
|
bucketLeafFlag = 0x01
|
|
)
|
|
|
|
type pgid uint64
|
|
|
|
type page struct {
|
|
id pgid
|
|
flags uint16
|
|
count uint16
|
|
overflow uint32
|
|
ptr uintptr
|
|
}
|
|
|
|
// typ returns a human readable page type string used for debugging.
|
|
func (p *page) typ() string {
|
|
if (p.flags & branchPageFlag) != 0 {
|
|
return "branch"
|
|
} else if (p.flags & leafPageFlag) != 0 {
|
|
return "leaf"
|
|
} else if (p.flags & metaPageFlag) != 0 {
|
|
return "meta"
|
|
} else if (p.flags & freelistPageFlag) != 0 {
|
|
return "freelist"
|
|
}
|
|
return fmt.Sprintf("unknown<%02x>", p.flags)
|
|
}
|
|
|
|
// meta returns a pointer to the metadata section of the page.
|
|
func (p *page) meta() *meta {
|
|
return (*meta)(unsafe.Pointer(&p.ptr))
|
|
}
|
|
|
|
// leafPageElement retrieves the leaf node by index
|
|
func (p *page) leafPageElement(index uint16) *leafPageElement {
|
|
n := &((*[maxNodesPerPage]leafPageElement)(unsafe.Pointer(&p.ptr)))[index]
|
|
return n
|
|
}
|
|
|
|
// leafPageElements retrieves a list of leaf nodes.
|
|
func (p *page) leafPageElements() []leafPageElement {
|
|
return ((*[maxNodesPerPage]leafPageElement)(unsafe.Pointer(&p.ptr)))[:]
|
|
}
|
|
|
|
// branchPageElement retrieves the branch node by index
|
|
func (p *page) branchPageElement(index uint16) *branchPageElement {
|
|
return &((*[maxNodesPerPage]branchPageElement)(unsafe.Pointer(&p.ptr)))[index]
|
|
}
|
|
|
|
// branchPageElements retrieves a list of branch nodes.
|
|
func (p *page) branchPageElements() []branchPageElement {
|
|
return ((*[maxNodesPerPage]branchPageElement)(unsafe.Pointer(&p.ptr)))[:]
|
|
}
|
|
|
|
// dump writes n bytes of the page to STDERR as hex output.
|
|
func (p *page) hexdump(n int) {
|
|
buf := (*[maxAllocSize]byte)(unsafe.Pointer(p))[:n]
|
|
fmt.Fprintf(os.Stderr, "%x\n", buf)
|
|
}
|
|
|
|
type pages []*page
|
|
|
|
func (s pages) Len() int { return len(s) }
|
|
func (s pages) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
|
|
func (s pages) Less(i, j int) bool { return s[i].id < s[j].id }
|
|
|
|
// branchPageElement represents a node on a branch page.
|
|
type branchPageElement struct {
|
|
pos uint32
|
|
ksize uint32
|
|
pgid pgid
|
|
}
|
|
|
|
// key returns a byte slice of the node key.
|
|
func (n *branchPageElement) key() []byte {
|
|
buf := (*[maxAllocSize]byte)(unsafe.Pointer(n))
|
|
return buf[n.pos : n.pos+n.ksize]
|
|
}
|
|
|
|
// leafPageElement represents a node on a leaf page.
|
|
type leafPageElement struct {
|
|
flags uint32
|
|
pos uint32
|
|
ksize uint32
|
|
vsize uint32
|
|
}
|
|
|
|
// key returns a byte slice of the node key.
|
|
func (n *leafPageElement) key() []byte {
|
|
buf := (*[maxAllocSize]byte)(unsafe.Pointer(n))
|
|
return buf[n.pos : n.pos+n.ksize]
|
|
}
|
|
|
|
// value returns a byte slice of the node value.
|
|
func (n *leafPageElement) value() []byte {
|
|
buf := (*[maxAllocSize]byte)(unsafe.Pointer(n))
|
|
return buf[n.pos+n.ksize : n.pos+n.ksize+n.vsize]
|
|
}
|
|
|
|
// PageInfo represents human readable information about a page.
|
|
type PageInfo struct {
|
|
ID int
|
|
Type string
|
|
Count int
|
|
OverflowCount int
|
|
}
|